Re: [Qemu-devel] Developing new user-level target?

From: Fabrice Bellard <fabrice@bellard.org>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Developing new user-level target?
Date: Sat, 10 Jul 2004 17:57:00 +0200	[thread overview]
Message-ID: <40F011CC.6080909@bellard.org> (raw)
In-Reply-To: <BAY8-F114YEcSvtxgBc0000e0d6@hotmail.com>

Hi,

User level emulation in QEMU only supports Linux as host _and_ guest. 
Supporting a different Unix would be very difficult except for simple 
console programs.

If the hardware is simple enough, it would be better to go for full 
system emulation right from the beginning.

Fabrice.

Patrick Mackinlay wrote:
> In searching across the net, I've managed to stumble across QEMU, which 
> may be the best starting point for a project I have in mind. I'd like 
> some feedback on the difficulty of doing what I propose, or if there are 
> any more appropriate systems that people are aware of that may better 
> satisfy my requirements.
> 
> Essentially, I have an interest in some older (mid to late 80's) UNIX 
> computer systems. The one I'm particularly interested in used the 
> CLIPPER processor (one of the first fully commercialised RISC CPUs) and 
> a version of SVR3 named CLIX.
> 
> I'm interested in adding support for this system to QEMU. In the first 
> instance, I'd like to get a user-level target working. Without having 
> looked at any of the source yet, can someone comment on the difficulty 
> of adding support for a new CPU? Following that, my next biggest concern 
> is supporting not only the COFF executable format (does QEMU support 
> only ELF at the moment?), but the translation from the native to Linux 
> system calls.
> 
> As a final complexity, I'd like to (eventually) host all this on Windows 
> - either natively under Win32, or more probably under the Interix 
> subsystem included in Microsoft's Services For Unix (SFU). Again, the 
> question arises regarding the system call translation component - how 
> much work is involved in adapting this to suit a different (although 
> still UNIX) target and a non-Linux host?
> 
> BTW, before anyone asks, I'm specifically interested in the user-level 
> target right now. Producing a full system level emulation is 
> interesting, but I have almost no documentation of the other system 
> hardware and I think it's going to be quite an exercise in 
> reverse-engineering to figure out enough to write emulation code.
> 
> Regards,
> Pat Mackinlay.
> 
> 
> 
> 
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